Newsweek's ousted bureau chief in Johannesburg describes the tender as well as the vengeful, spiteful side of the Afrikaners, the ""strange and hopeless world'' of the Anglos, the elusive black leadership, the growing violence and brutality of black slum children and the forthrightness of Winnie Mandela and Desmond Tutu . When an Anglo banker asked Archbishop Tutu what concerned liberal businessmen could do to help in the struggle, Tutu replied: ``Stop paying taxes. Stop supporting this cruel and immoral regime with your money.'' Manning believes that despite their differences, Jimmy Carter and Ronald Reagan strengthened apartheid, and that in less than six years, through his ``constructive engagement,'' Reagan destroyed a quarter-century of good will toward the U.S. in black South Africa. A painful, tragic book. (September 25)